Regional Azure Authorities

AAD is adding support for regional STS (ESTSR). Currently only S2S (client_credentials) flow and available via opt-in.

Region detection

If you know the region - use it. If you don't know the region, MSAL can attempt auto-discovery. If this fails, the non-regional authority is used.

// if app knows the region, use it as MSAL cannot reliably detect it
string region = Config.Region ?? ConfidentialClientApplication.AttemptRegionDiscovery;

var cca = ConfidentialClientApplicationBuilder(client_id)
                  .WithAuthority(AzureCloud.PublicCloud, validateAuthority:false)
                  .WithRegion(region)  
                  .Build();

Authority validation

Regional authorities cannot be validated.